The spatial computing revolution is coming! This talk introduces the main components of how different AR and VR headsets work. The talk covers everything from the optics, through controllers, spatial audio, to tracking and sensors to give a clear understanding of how the state of the art technologies work, what are their strong points and limitations of each approach. If you listen to this talk, you'll have a clear understanding of the capabilities of all major AR and VR headsets, from HoloLens, HoloLens 2, Magic Leap One, Vive, Vive Pro, Oculus Rift, Oculus Quest and others.